In the mid-1970s, when pianist Bob James and guitarist Earl Klugh made their first records, jazz underwent a shift.

Many players -- and James and Klugh were two of them -- began incorporating elements of rock, pop and other forms with jazz improvisation. At first, this new genre was called "contemporary jazz." Lately, it's known as "smooth jazz," a term James is not totally comfortable with.

"I tend to say to say that music is sometimes smooth, sometimes rough," says James, who Sunday appears with Klugh at the 2nd Annual Liberty Jazz Festival (see accompanying story for details).

"Radio stations concentrate on smooth, it's a format that has worked," James says. "I'm just happy to get my music played, though I don't think of myself as 'smooth' simply because it does."

Asked what he calls his music, James -- who has persuasively played everything from avant-garde to swinging mainstream to contemporary -- says he doesn't think about it.

"I just love being associated with jazz, one way or another," says the 67-year-old native of Marshall, Mo., who lives in Traverse, Mich., and who has played with such aces as Sarah Vaughan and Maynard Ferguson.

"Still, I've always believed there's no one pure way of playing. It depends on the personality of the individual, the time we live in. Music should be constantly evolving as far I'm concerned."

James -- who is also in the cooperative contemporary quartet, Fourplay -- admits that keeping his own music fresh is no easy thing.

"I'm subject to the same habits that we all are," he says. "I'm also aware that at a performance, fans have an expectation (of pieces they want to hear). It's a dilemma."

One way to be fresh is to try something completely different, as James did on his 2006 Koch CD "Angels of Shanghai," combining Chinese music with jazz. "That forced me out of my comfort zone," he says.

Last year, James also released another Koch CD, "Urban Flamingo," which was closer to his comfort zone, his usual contemporary jazz style. The album features Klugh and the rhythm section they'll use Sunday: drummer Ron Otis, bassist Al Turner and percussionist Doc Gibbs.

The pianist and the guitarist met in the late-1970s, when Klugh guested on James' "Touchdown" (CTI), which led to the first of their three co-leader recordings, 1979's "One on One" (Columbia). The latter was "magic," James says.

"It was one of the smoothest projects I had ever done in terms of how quickly it came together, how well we got along, how we thought about music," he says. "We knew there was some magic, and knew we should stay with it."

They have, and along with intermittent tours and performances around the world, they have made two other co-led CDs: 1992's "Cool" (Warner Bros.), and 1982's "Two of a Kind" (Manhattan).

Asked what he liked about Klugh, James hardly paused. "He's sensitive to what's going on around him, and he's a beautiful player of melodies," he says. "As a result he also writes great melodies, and his compositions are always fun to play. He also has a very positive attitude."

At the festival, James and Klugh will offer a selection of their favorites, perhaps the guitarist's "New York Samba" or the ballad, "Heart String," maybe James' hit, "Westchester Lady," one often sampled by hip-hoppers.

He will play acoustic piano, with occasional forays on synthesizers. James began on the instrument at age 5, and has long favored it over plugged-in instruments.

"There isn't anything in the synthesizer world that compares with the full dynamic range of the piano," he says. "My touch, my desire to play solos, they're rooted in the piano."

Asked to name his favorite pianists, James picked two Jersey treasures: Plainfield native Bill Evans and Count Basie, from Red Bank.

"They both have been, in very different ways, influential to me, and still loom very big in what pushes me," James says. "Basie was a motivator of large ensemble music where the piano was not doing that much, then when the piano did come in, it drove the music in an amazing way. That always inspired me, and I tried to emulate it. With Bill, it was his control over voicings, his mastery of soloing in a way where every note meant something. That was very powerful. I couldn't imagine any note being any better."

Zan Stewart is the Star-Ledger's jazz writer. He is also a musician who occasionally performs at local clubs. He may be reached at zstewart@starledger.com or at (973) 324-9930.
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Check List:
The festival allows cameras, lawn chairs, blankets, and hand-held umbrellas but does not allow any beverages (no water), food, coolers, grills, or large beach-type umbrellas. Numerous food and beverage vendors will be on hand for the entirety of the festival. All attendees are allowed exit and re-entry to the festival site. Please visit www.nj.com/libertyjazzfestival for complete festival guidelines.

Getting There:
From New Jersey: Take the New Jersey Turnpike to Exit 14C. After tolls, get in right lane and exit down the ramp to a stop sign. Follow signs to Jazz Festival Parking.

From Manhattan via the Holland Tunnel: Follow signs to New Jersey Turnpike, take Exit 14B. Bear left after the toll and follow signs to Jazz Festival Parking. Parking is $5 for most lots. Continuous shuttle bus service is available throughout the festival.

Public transportation:
New Jersey Transit Hudson-Bergen Light Rail System: Get off at Liberty State Park. Shuttle bus service available. For information, call (800) 772-2222.